Re: [RFC] How to (automatically) find the correct maintainer(s)

[Stefan Richter]

On 13 Jan, Richard Knutsson wrote:
> Stefan Richter wrote:
>> On 13 Jan, Richard Knutsson wrote:
>> [...]
>>   
>>> SUPERCOOL ALPHA CARD
>>>
>>> P:	Clark Kent
>>> M:	superman@xxxxxxxxxx
>>> L:	some@xxxxxxxxx
>>> C:	SUPER_A
>>> S:	Maintained
>>> (C: for CONFIG. Any better idea?)
>>>
>>> then if someone changes a file who are built with CONFIG_SUPER_A, can 
>>> easily backtrack it to the correct maintainer(s).
>>>     
>> [...]
>>   
>>> My first idea was to use the pathway and define that directories above 
>>> the specified (if not specified by another) would fall to the current 
>>> maintainer. It would work, but requires that all pathways be specified 
>>> at once, or a few maintainers with "short" pathways would get much of 
>>> the patches (and it is not as correct/easy to maintain as looking for 
>>> the CONFIG_flag).
>>>
>>>
>>> Any thoughts on this is very much appreciated (is there any flaws with 
>>> this?).
>>>     
>>
>>  - What about drivers which have no MAINTAINER entry but reside in a
>>    subsystem with MAINTAINER entry?
>>   
> Hmm, how are those drivers built? Can you please point me to one?

I believe you read too quickly what I wrote, didn't you? :-)
The MAINTAINER file doesn't influence how drivers are built.

>>  - What if these drivers depend on two subsystems?
>>   
> Not sure if I understand the problem. I don't see the maintainers for 
> the subsystems too interested in a driver, and it is the drivers 
> maintainer we want.

I am specifically thinking of drivers which are maintained by the
subsystem maintainers. (Well, see below...)

Besides, the subsystem maintainer could point the submitter to a
more appropriate channel or ignore the submitter. (A submitter who
feels ignored is hopefully doing some more research then.) Also,
a driver maintainer certainly reads the mailinglist to which the
submitter posted.

>>  - Config options map to object files but do not map directly to source
>>    files. Diffstats show source files.
>>   
> Can you make a object-file out of 2 c-files? Using Makefile?

Yes, you can, although I don't know if it is directly done in the
kernel build system. Of course what is often done is to make n object
files out of n c files, then link them to make 1 object file.

>> Example: The sbp2 driver is an IEEE 1394 driver and a SCSI driver.
>> sbp2.o is enabled by CONFIG_IEEE1394_SBP2 which depends on
>> CONFIG_IEEE1394 and CONFIG_SCSI. sbp2.c resides in drivers/ieee1394/.
>> What is the algorithm to look up sbp2's maintainers?
>>   
> The one listed for CONFIG_IEEE1394_SBP2 :)

...OK, we /could/ write

IEEE 1394 SUBSYSTEM
C:	IEEE1394
C:	IEEE1394_OHCI1394
C:	IEEE1394_SBP2
C:	IEEE1394_DV1394  /* would better be put into a new own entry due to different status of maintenance level */
C:	IEEE1394_VIDEO1394  /* that one perhaps too */
L:	linux1394-devel@xxxxxxxxxxxxxxxxxxxxx
P:	Ben and me
[...]
IEEE 1394 IPV4 DRIVER (eth1394)
C:	IEEE1394_ETH1394
[...]

On the other hand, we could write

IEEE 1394 SUBSYSTEM
F:	drivers/ieee1394
L:	linux1394-devel@xxxxxxxxxxxxxxxxxxxxx
P:	Ben and me
[...]
IEEE 1394 IPV4 DRIVER (eth1394)
F:	drivers/ieee1394/eth1394
[...]

If it was done the latter way, i.e. using F: not C:, it could be
made a rule that the more specific entries come after more generic
entries. Thus the last match of multiple matches is the proper one.
In any case, the longest match is the proper one.

> But what about ex ieee1394_core.o? Is ieee1394-objs "equal" to 
> ieee1394.o? (Seems I need to read some Makefile docs...)

Yes and yes. (Documentation/kbuild/makefiles.txt)

>> Don't get me wrong though. Easier lookup of maintainers and mailinglists
>> sounds to me like a desirable feature, not just from the point of view
>> of submitters but also of maintainers.
>>   
> Well, as they say: "If it is too good to be true, it usually is" (but I 
> don't think it is too far fetched)

No, it probably isn't.

> (Btw, what I can see, there is no possibility to get the wrong 
> maintainer. Just that sometime it can't give you an answer and you have 
> to do it in the old way).

Your approach could give a wrong answer if someone implements a
very "clever" mapping. My approach could give a wrong answer if
someone takes a generic match while there was a more specific
match.

Your approach requires to evaluate the diffstat, one or more
Makefile (taking the Linux Makefile syntax into account), and the
MAINTAINERS file. My approach just requires to evaluate the
diffstat and the MAINTAINERS file.
-- 
Stefan Richter
-=====-=-=== ---= -==-=
http://arcgraph.de/sr/

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